<?xml version="1.0" encoding="UTF-8"?><rss version="2.0"
	xmlns:content="http://purl.org/rss/1.0/modules/content/"
	xmlns:wfw="http://wellformedweb.org/CommentAPI/"
	xmlns:dc="http://purl.org/dc/elements/1.1/"
	xmlns:atom="http://www.w3.org/2005/Atom"
	xmlns:sy="http://purl.org/rss/1.0/modules/syndication/"
	xmlns:slash="http://purl.org/rss/1.0/modules/slash/"
	>

<channel>
	<title>surface albedo &#8211; Science</title>
	<atom:link href="https://scienmag.com/tag/surface-albedo/feed/" rel="self" type="application/rss+xml" />
	<link>https://scienmag.com</link>
	<description></description>
	<lastBuildDate>Fri, 09 Oct 2026 17:38:59 +0000</lastBuildDate>
	<language>en-US</language>
	<sy:updatePeriod>
	hourly	</sy:updatePeriod>
	<sy:updateFrequency>
	1	</sy:updateFrequency>
	<generator>https://wordpress.org/?v=7.1.3</generator>

<image>
	<url>https://scienmag.com/wp-content/uploads/2024/07/cropped-scienmag_ico-32x32.jpg</url>
	<title>surface albedo &#8211; Science</title>
	<link>https://scienmag.com</link>
	<width>32</width>
	<height>32</height>
</image> 
<site xmlns="com-wordpress:feed-additions:1">73899611</site>	<item>
		<title>Why Some Power Plant Pollution Plumes Vanish From Satellite View</title>
		<link>https://scienmag.com/why-some-power-plant-pollution-plumes-vanish-from-satellite-view/</link>
		
		<dc:creator><![CDATA[Russell Cooper]]></dc:creator>
		<pubDate>Fri, 09 Oct 2026 17:38:59 +0000</pubDate>
				<category><![CDATA[Athmospheric]]></category>
		<category><![CDATA[Technology and Engineering]]></category>
		<category><![CDATA[Air pollution]]></category>
		<category><![CDATA[atmospheric measurement techniques for pollution]]></category>
		<category><![CDATA[challenges in detecting invisible pollution plumes]]></category>
		<category><![CDATA[detectability]]></category>
		<category><![CDATA[effects of terrain and surface brightness on pollution plumes]]></category>
		<category><![CDATA[emissions monitoring]]></category>
		<category><![CDATA[environmental monitoring using satellite imagery]]></category>
		<category><![CDATA[impact of geographic and atmospheric factors on pollution visibility]]></category>
		<category><![CDATA[implications for air quality tracking from space]]></category>
		<category><![CDATA[Machine learning]]></category>
		<category><![CDATA[nitrogen dioxide]]></category>
		<category><![CDATA[nitrogen dioxide pollution from power plants]]></category>
		<category><![CDATA[NOx]]></category>
		<category><![CDATA[plume detection]]></category>
		<category><![CDATA[power plant emission visibility]]></category>
		<category><![CDATA[power plants]]></category>
		<category><![CDATA[satellite monitoring of global power plant emissions]]></category>
		<category><![CDATA[satellite remote sensing]]></category>
		<category><![CDATA[Satellite-based air pollution detection]]></category>
		<category><![CDATA[Sentinel-5P]]></category>
		<category><![CDATA[surface albedo]]></category>
		<category><![CDATA[TROPOMI]]></category>
		<category><![CDATA[TROPOMI satellite observations]]></category>
		<category><![CDATA[wind influence on satellite pollution detection]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=255141</guid>

					<description><![CDATA[A machine learning analysis of over 6,000 power plants shows that identical emissions can be visible or invisible to satellites depending on wind, terrain, surface brightness, and viewing angle.]]></description>
										<content:encoded><![CDATA[<p>Every day, a European satellite sweeps over the planet&#8217;s power plants, searching for faint traces of nitrogen dioxide in the sunlight reflected from Earth&#8217;s surface. Some of the world&#8217;s largest polluters announce themselves clearly, their exhaust plumes painting unmistakable streaks across the satellite images. Others, emitting nearly identical amounts of pollution, remain stubbornly invisible. A new study has finally explained why, and the answer has major implications for how the world tracks air pollution from orbit.</p>
<p>Researchers Ruizhe Huang and Sherrie Wang of the Massachusetts Institute of Technology analyzed more than 1.5 million satellite observations of over 6,000 power plants worldwide, drawing on data from the TROPOspheric Monitoring Instrument, or TROPOMI, aboard the Copernicus Sentinel-5P satellite. Their findings, published in the journal Atmospheric Measurement Techniques, represent the first global, data-driven account of when and where power plant nitrogen dioxide plumes become visible from space. The work reveals that detectability is not simply a function of how much a plant pollutes. Instead, it emerges from an intricate interplay of wind, terrain, surface brightness, and the geometry of the satellite&#8217;s view.</p>
<p>The scale of the analysis is unprecedented. For the United States, the team paired TROPOMI observations from 2019 through 2024 with hourly emissions records from the Environmental Protection Agency&#8217;s Continuous Emissions Monitoring Systems, covering the 500 largest power sector emitters of nitrogen oxides. Globally, they used annual emission estimates from the CoCO2 catalog for the 6,000 highest-emitting plants, spanning coal, natural gas, oil, biomass, and waste facilities. After quality filtering, the dataset contained 666,222 high-quality US observations and 875,686 global ones, each capturing a single satellite overpass of a specific plant.</p>
<p>A central challenge was teaching a computer to recognize a plume and correctly attribute it to its source. The researchers developed an automated algorithm that masks potential interference from nearby cities and other power plants, uses wind direction to define a downwind search zone, calculates the background nitrogen dioxide concentration from upwind air, and then applies a dual threshold requiring both statistical significance and an absolute minimum signal strength. Validated against 800 manually labeled observations stratified by continent and emission level, the algorithm achieved 98 percent accuracy in both US and global tests, a level of reliability that made the subsequent analysis possible.</p>
<p>Even with this powerful detection tool, the researchers found that geography matters enormously. Among 171 US plants that survived the study&#8217;s strict interference filtering, per-plant detectability ranged from 6 percent to 85 percent of overpasses. Globally, among 1,065 plants, the range stretched from zero to 100 percent, with a median of 27.8 percent. The pattern follows a striking geographic logic: detectability is highest in arid and semi-arid regions such as the American interior West, Iberia, North Africa, Greece and Turkey, and eastern Australia, and lowest in humid, cloudy regions where bright surfaces are rare and cloud cover frequently spoils the retrieval.</p>
<p>To untangle the physical causes, the team trained a machine learning model, a multi-layer perceptron neural network, to predict whether a plume would be detectable from 25 variables describing the sensor, the plant, the meteorology, and the environment. The model performed well, achieving F1 scores above 0.66 and areas under the curve exceeding 0.8. Feature importance analysis using permutation scores and SHAP values identified six dominant factors: the nitrogen oxide emission rate, surface altitude, surface albedo in the nitrogen dioxide spectral window, the satellite&#8217;s viewing zenith angle, the plant&#8217;s primary fuel type, and wind speed.</p>
<p>Some of these relationships confirm long-standing theory. Higher emissions produce more concentrated plumes and higher detection probability, and brighter surfaces improve the signal-to-noise ratio of the retrieval by increasing the amount of light available for absorption spectroscopy. Wind speed works in the opposite direction: strong winds stretch and dilute a plume, lowering the concentration contrast that the satellite must detect. The dependence on viewing angle proved more subtle, with detectability peaking at intermediate off-nadir angles, near 20 degrees globally and 35 degrees for US plants, where the longer optical path through the lower atmosphere amplifies the absorption signal before oblique geometry begins to degrade the retrieval.</p>
<p>The numbers offer a practical benchmark. For US power plants, an average hourly emission rate of roughly 400 kilograms of nitrogen oxides corresponds to about a 50 percent chance of detection, but under different combinations of wind, albedo, and viewing geometry, the same emission rate can yield detection probabilities anywhere from below 20 percent to above 60 percent. The researchers illustrate this with individual facilities: a low-emitting plant with dark surfaces and modest winds reached only 18 percent detectability, while a plant emitting eight times as much, blessed with bright terrain and calm air, achieved 64 percent. Identical pollution, in short, can be seen or missed depending entirely on local conditions.</p>
<p>The study also exposed a sobering limitation of current satellite monitoring. To ensure that detected plumes could be attributed to a single source, the researchers excluded any plant within 20 kilometers of another major power plant or within 45 to 90 kilometers of a large city, depending on the city&#8217;s size. This filtering removed a staggering share of the world&#8217;s monitoring targets: 82.3 percent of the 6,000 global plants fell inside interference zones, leaving just 21.1 percent of their combined emissions in the analysis. In the United States, where emission sources are less clustered, 45 percent of emissions survived the filter. The finding underscores how difficult it remains to monitor pollution from the densely industrialized regions where it matters most.</p>
<p>The implications reach well beyond this single study. The same variables that govern whether a plume is visible also shape how it appears, meaning that emission-quantification methods could become more accurate by explicitly accounting for wind, albedo, and viewing geometry as auxiliary variables or priors. And as a new generation of satellites comes online, including missions targeting pixel sizes of a few kilometers or even 300 meters, finer spatial resolution should reduce plume dilution and interference, potentially bringing many more of the world&#8217;s power plants within reach of space-based monitoring. For now, the study provides the first empirical map of where today&#8217;s satellites can and cannot see, a foundation for turning orbital observations into trustworthy global emission accounts.</p>
<p><strong>Subject of Research:</strong> Satellite detectability of nitrogen dioxide plumes from power plants</p>
<p><strong>Article Title:</strong> Global variability in the detectability of power plant NO2 plumes from space</p>
<p><strong>Article References:</strong> Huang, R., &amp; Wang, S. (2026). Global variability in the detectability of power plant NO 2 plumes from space. <em>Atmospheric Measurement Techniques, 19</em>(18), 6099-6124. <a href="https://doi.org/10.5194/amt-19-6099-2026" rel="noopener noreferrer">https://doi.org/10.5194/amt-19-6099-2026</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.5194/amt-19-6099-2026" rel="noopener noreferrer">10.5194/amt-19-6099-2026</a></p>
<p><strong>Keywords:</strong> nitrogen dioxide, power plants, TROPOMI, satellite remote sensing, air pollution, machine learning, emissions monitoring, plume detection, Sentinel-5P, NOx, surface albedo, detectability</p>
]]></content:encoded>
					
		
		
		<post-id xmlns="com-wordpress:feed-additions:1">255141</post-id>	</item>
		<item>
		<title>Massive tree-planting schemes may backfire by stripping away cooling clouds</title>
		<link>https://scienmag.com/massive-tree-planting-schemes-may-backfire-by-stripping-away-cooling-clouds/</link>
		
		<dc:creator><![CDATA[Russell Cooper]]></dc:creator>
		<pubDate>Fri, 09 Oct 2026 09:26:46 +0000</pubDate>
				<category><![CDATA[Athmospheric]]></category>
		<category><![CDATA[Chemistry]]></category>
		<category><![CDATA[afforestation]]></category>
		<category><![CDATA[atmospheric modeling of climate interventions]]></category>
		<category><![CDATA[bioenergy crop expansion risks]]></category>
		<category><![CDATA[bioenergy crops]]></category>
		<category><![CDATA[CESM climate model]]></category>
		<category><![CDATA[CESM climate simulations]]></category>
		<category><![CDATA[Climate Change Mitigation]]></category>
		<category><![CDATA[Climate Mitigation]]></category>
		<category><![CDATA[cloud cover and planetary cooling]]></category>
		<category><![CDATA[cloud radiative effect]]></category>
		<category><![CDATA[forest expansion and regional warming]]></category>
		<category><![CDATA[forest-based climate solutions]]></category>
		<category><![CDATA[land use change]]></category>
		<category><![CDATA[land-use transformation effects]]></category>
		<category><![CDATA[large-scale tree planting impacts]]></category>
		<category><![CDATA[low-level cloud dynamics]]></category>
		<category><![CDATA[low-level clouds]]></category>
		<category><![CDATA[Northern Hemisphere]]></category>
		<category><![CDATA[planetary boundary layer]]></category>
		<category><![CDATA[regional climate feedbacks]]></category>
		<category><![CDATA[relative humidity]]></category>
		<category><![CDATA[surface albedo]]></category>
		<category><![CDATA[unintended consequences of afforestation]]></category>
		<category><![CDATA[warming hotspots]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=253005</guid>

					<description><![CDATA[A new climate modeling study finds that large-scale idealized forest and bioenergy expansion can accelerate the loss of cooling low-level clouds and amplify regional warming, while realistic, spatially targeted afforestation avoids this cloud-mediated penalty.]]></description>
										<content:encoded><![CDATA[<p>Planting trees has become the world&#8217;s favorite climate remedy, a strategy celebrated for its simplicity: put more forests on the land, and they will pull carbon dioxide out of the sky. But a new modeling study published in Atmospheric Chemistry and Physics suggests that the story is far more complicated than the carbon ledger alone. When researchers simulated large-scale forest and bioenergy expansion through the end of the century, they found that these land-use transformations can quietly sabotage one of the planet&#8217;s most important cooling mechanisms, the low-level clouds that shade the surface from sunlight. In the worst-case scenario, the loss of these clouds was fast enough to amplify regional warming rather than restrain it.</p>
<p>The research team, led by Nanjian Liu and Zhixin Hao of the Institute of Geographic Sciences and Natural Resources Research at the Chinese Academy of Sciences, together with colleagues at the University at Buffalo and the Institute of Mountain Hazards and Environment, ran transient simulations with the fully coupled Community Earth System Model, or CESM, under a moderate emissions pathway spanning 2015 to 2100. They compared four futures: a control run in which land cover stayed frozen at 2015 levels, an idealized scenario in which roughly 29.3 million square kilometers of grassland and shrubland were converted to forest, an idealized bioenergy expansion in which sugarcane cultivation grew by 6.4 million square kilometers, and a realistic afforestation pathway drawn from published mitigation scenarios, involving about 7.5 million square kilometers of new forest concentrated in tropical South America, Central Africa, and central North America.</p>
<p>The numbers that emerged are striking. In the control simulation, global low-level cloud cover declined at a rate of 0.0153 percent per year. Under the idealized afforestation scenario, that loss accelerated to 0.0175 percent per year, a factor of 1.14 globally, but a factor of 1.52 over land. In the Northern Hemisphere mid-to-high latitudes, the effect was even more dramatic: the rate of low-cloud loss in affected land regions reached twenty times that of the Southern Hemisphere overall. Meanwhile, high-level clouds, the thin cirrus veils that trap outgoing heat and warm the planet, increased 1.5 times faster than in the control run. Bioenergy expansion produced a similar but weaker signature, while the realistic afforestation scenario did the opposite, slowing the loss of low- and mid-level clouds and suppressing regional warming.</p>
<p>The physical mechanism the authors identify is a cascade that begins with color. Forests are darker than grasslands and shrublands, so replacing those biomes reduces surface albedo, causing the land to absorb more solar radiation. In the late stages of the idealized afforestation simulation, land surface albedo dropped by 0.0142 in Northern Hemisphere mid-to-high latitudes, about 2.4 times the global average, and net surface radiation over land rose by 2.43 watts per square meter, roughly 3.3 times the global mean. That extra energy is preferentially channeled into sensible heat, the turbulent heat that warms the air directly, rather than into evaporation. The result is a deeper, more vigorously mixed planetary boundary layer that entrains dry air from the free troposphere above.</p>
<p>That drying of the boundary layer is what kills the clouds. As relative humidity falls, the lifting condensation level, the altitude at which water vapor begins to condense into droplets, rises faster than the boundary layer itself grows. When moisture can no longer reach saturation before escaping into the overlying subsaturated air, shallow cumulus clouds fail to form or dissipate prematurely. The study&#8217;s interpretable machine-learning analysis, which used an XGBoost model with SHAP attribution to rank the drivers of simulated cloud trends, independently confirmed this chain of logic: changes in relative humidity were the highest-ranked predictor of low-level cloud trends under all three land-use scenarios, with normalized importance values of 20.4 percent, 20.4 percent, and 15.3 percent for the idealized afforestation, bioenergy, and realistic scenarios respectively. For total cloud cover, total precipitable water dominated, underscoring how profoundly large-scale land conversion disturbs the hydrological cycle.</p>
<p>The radiative consequences follow directly. Low clouds are the planet&#8217;s parasol, reflecting sunlight with high albedo, so their accelerated loss strengthens positive shortwave cloud radiative forcing, meaning clouds reflect less and less of the sun&#8217;s energy. At the same time, the growth of high-level clouds enhances longwave warming by trapping infrared radiation. In the boreal zone between 50 and 90 degrees north, idealized afforestation amplified warming to 2.15 times the global average, and bioenergy expansion to 1.71 times, while realistic afforestation produced cooling there. The team also quantified the geography of this disruption using Gini coefficients, an inequality metric borrowed from economics: under idealized afforestation, the Northern Hemisphere Gini index for low-cloud loss rose from 0.41 to 0.50, showing that cloud depletion became intensely concentrated in specific latitudinal bands rather than spread evenly across the globe.</p>
<p>Perhaps the most unsettling finding is that the damage does not stay where the trees are planted. The simulations show that surface darkening and sensible heating generate anomalous wind fields that transport warm air downwind, and that the resulting thermal anomalies excite quasi-stationary Rossby waves whose energy propagates eastward and poleward through the mid-troposphere. In one striking example, realistic afforestation accelerated low-level cloud loss on the western side of South America even though the forests in that scenario were planted on the continent&#8217;s eastern side, a spatial decoupling the authors attribute to remote biophysical teleconnections. Such remotely driven cloud loss, they note, could carry serious implications for cloud-mediated drought risk in dynamically linked regions hundreds or even thousands of kilometers from the original land conversion.</p>
<p>The contrast between the idealized and realistic scenarios carries the study&#8217;s central policy message. The idealized experiment followed the strict Food and Agriculture Organization definition of afforestation, establishing new forest on land that was never forest, in this case grasslands and shrublands, much of it in water-limited mid-to-high latitudes where the transpiration boost from trees is too weak to offset the albedo-driven drying. The realistic pathway, by contrast, distributed forest expansion more selectively, sustaining evapotranspiration efficiency and allowing atmospheric cooling to partially neutralize the albedo effect. The authors caution that their idealized scenario is not a recommendation but a warning: because many real-world tree-planting initiatives have indeed targeted natural grasslands and shrublands, the climate benefits conventionally attributed to afforestation may be substantially overestimated, and conflating true afforestation with reforestation or forest enhancement distorts assessments of mitigation efficiency.</p>
<p>The researchers are candid about the limits of their work. CESM&#8217;s cloud microphysics, governed by the MG2 two-moment scheme and the CLUBB turbulence parameterization, carries documented uncertainties in ice nucleation, autoconversion rates, and mixed-phase cloud partitioning, which means the simulated cloud loss and its downstream warming hotspots may represent an upper bound of the model-dependent range. The high-cloud response, defined purely by cloud-top pressure, aggregates cirrus and convective anvils and cannot be pinned to a single mechanism. Still, the qualitative conclusion is robust within the model framework and consistent with satellite-observed declines in low-level cloud cover that have been linked to recent record temperatures and a widening planetary energy imbalance. As governments pour billions into tree-planting pledges and bioenergy deployment, the study argues that climate policy must look beyond carbon sequestration alone and explicitly account for albedo, moisture, and the clouds that hang in the balance. The right trees in the right places can still help cool the planet; the wrong conversions, at the wrong scale, may do the opposite.</p>
<p><strong>Subject of Research:</strong> Cloud cover responses to large-scale afforestation and bioenergy crop expansion in coupled climate model simulations</p>
<p><strong>Article Title:</strong> Forest and bioenergy expansion amplifies climate warming by accelerating regional cloud loss</p>
<p><strong>Article References:</strong> Liu, N., Hao, Z., Xia, S., &amp; Zhao, P. (2026). Forest and bioenergy expansion amplifies climate warming by accelerating regional cloud loss. <em>Atmospheric Chemistry and Physics, 26</em>(19), 14133-14163. <a href="https://doi.org/10.5194/acp-26-14133-2026" rel="noopener noreferrer">https://doi.org/10.5194/acp-26-14133-2026</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.5194/acp-26-14133-2026" rel="noopener noreferrer">10.5194/acp-26-14133-2026</a></p>
<p><strong>Keywords:</strong> afforestation, bioenergy crops, low-level clouds, cloud radiative effect, CESM climate model, surface albedo, planetary boundary layer, relative humidity, warming hotspots, land use change, Northern Hemisphere, climate mitigation</p>
]]></content:encoded>
					
		
		
		<post-id xmlns="com-wordpress:feed-additions:1">253005</post-id>	</item>
		<item>
		<title>Satellite Records Reveal Thirty Years of Heat and Water Stress in Pakistan&#8217;s Twin Cities</title>
		<link>https://scienmag.com/satellite-records-reveal-thirty-years-of-heat-and-water-stress-in-pakistans-twin-cities/</link>
		
		<dc:creator><![CDATA[Violet Maxwell]]></dc:creator>
		<pubDate>Fri, 09 Oct 2026 07:13:10 +0000</pubDate>
				<category><![CDATA[Earth Science]]></category>
		<category><![CDATA[climate change Pakistan]]></category>
		<category><![CDATA[effects of urbanization on water and heat exchange]]></category>
		<category><![CDATA[evapotranspiration]]></category>
		<category><![CDATA[evapotranspiration increase]]></category>
		<category><![CDATA[impact of concrete on climate]]></category>
		<category><![CDATA[Islamabad]]></category>
		<category><![CDATA[land cover transformation Islamabad Rawalpindi]]></category>
		<category><![CDATA[land surface temperature]]></category>
		<category><![CDATA[land-cover change]]></category>
		<category><![CDATA[Landsat]]></category>
		<category><![CDATA[long-term climate monitoring]]></category>
		<category><![CDATA[NDVI]]></category>
		<category><![CDATA[Rawalpindi]]></category>
		<category><![CDATA[remote sensing]]></category>
		<category><![CDATA[satellite imagery urbanization]]></category>
		<category><![CDATA[SEBAL]]></category>
		<category><![CDATA[semi-arid mountain environment]]></category>
		<category><![CDATA[surface albedo]]></category>
		<category><![CDATA[surface heating urban expansion]]></category>
		<category><![CDATA[urban heat island]]></category>
		<category><![CDATA[urban heat island effect]]></category>
		<category><![CDATA[urban heat island research]]></category>
		<category><![CDATA[Urbanization]]></category>
		<category><![CDATA[water stress in South Asia]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=252465</guid>

					<description><![CDATA[A thirty-year satellite analysis of Islamabad and Rawalpindi shows that urban expansion has widened land surface temperature extremes and intensified evapotranspiration in a semi-arid mountain landscape.]]></description>
										<content:encoded><![CDATA[<p>In the foothills where the Margalla Hills meet the Pothohar Plateau, one of South Asia&#8217;s most ambitious planned capitals is quietly rewriting its own climate. A new study published in Theoretical and Applied Climatology has tracked three decades of land cover transformation across Islamabad and Rawalpindi, the twin cities of Pakistan, and found that the spread of concrete and asphalt has fundamentally altered how the landscape exchanges heat and water with the atmosphere. Using satellite imagery spanning from 1989 to 2019, the research team documented a sevenfold expansion of built-up settlement and a corresponding intensification of both surface heating and evapotranspiration, offering one of the most detailed portraits yet of how urbanization reshapes the energy balance of a semi-arid mountain environment.</p>
<p>The scale of the transformation is striking. In 1989, settlements occupied just 5.18 percent of the study area. By 2019, that figure had climbed to 36.51 percent, meaning more than a third of the landscape had been converted to urban fabric within a single generation. This is not merely a change in what the land looks like from above; it is a change in how the land behaves. Natural vegetation and soil, which once absorbed rainfall, shaded the ground, and released moisture back to the air, have been replaced by impervious surfaces that store solar energy during the day and radiate it slowly at night, driving the phenomenon scientists call the urban heat island.</p>
<p>To quantify these changes, the researchers drew on three generations of Landsat sensors: the Thematic Mapper, the Enhanced Thematic Mapper Plus, and the Operational Land Imager with its Thermal Infrared Sensor. By classifying land cover across multiple epochs and applying geographic information system techniques, they constructed a time series of land surface temperature, vegetation greenness, surface albedo, and evapotranspiration. The thermal record tells a clear story. In 1989, land surface temperatures across the region ranged from roughly 14 to 40 degrees Celsius. Thirty years later, the observed range had widened to between 12 and 42 degrees Celsius, with the hottest surfaces concentrated precisely where the newest development had spread.</p>
<p>The study&#8217;s most technically ambitious component was its use of the Surface Energy Balance Algorithm, known as SEBAL, to estimate evapotranspiration, the combined flux of water evaporated from soil and transpired by plants. SEBAL works by solving the energy budget at the land surface: incoming solar radiation is partitioned between sensible heat, which warms the air, and latent heat, which drives water vapor upward. By computing this partitioning pixel by pixel from satellite-derived radiometric temperature, albedo, and vegetation indices, the model converts thermal imagery into maps of daily water use across the landscape. The results revealed a substantial intensification of the water cycle, with evapotranspiration rising from 5.81 to 6.70 millimeters per day in the earlier period to 8.14 to 8.56 millimeters per day by 2019.</p>
<p>That increase may seem counterintuitive. Cities are usually associated with drying, not with more vigorous water fluxes. But the authors point to two interacting mechanisms. First, the Normalized Difference Vegetation Index, a standard satellite measure of green vegetation, actually increased over parts of the study area, reflecting both afforestation efforts and the expansion of irrigated gardens, lawns, and roadside plantings within the growing city. Second, changes in surface albedo, the fraction of sunlight reflected by the ground, altered the amount of energy available for evaporation. Where vegetated and irrigated surfaces expanded, more energy was channeled into latent heat, pushing evapotranspiration upward even as the surrounding built environment grew hotter and drier.</p>
<p>The spatial fingerprint of the urban heat island expanded accordingly. Heat island zones, identified where surface temperatures persistently exceeded those of the surrounding rural and vegetated landscape, spread across the urban cores of Islamabad and Rawalpindi, tracking the growth of housing schemes, commercial districts, and transport corridors. In a mountain and plateau setting, this pattern carries particular risks. Cool air drainage from the Margalla Hills once moderated nighttime temperatures in the valley settlements; as the urban footprint climbs the slopes and fills the basins, that natural ventilation is disrupted, and heat that would have escaped accumulates over neighborhoods with limited tree cover.</p>
<p>The consequences extend well beyond discomfort. Elevated land surface temperatures increase cooling energy demand, strain electrical grids during summer peaks, and worsen air quality by accelerating the photochemical reactions that produce ground-level ozone. Reduced infiltration on sealed surfaces diminishes groundwater recharge in a region already drawing heavily on its aquifers, while intensified evapotranspiration from irrigated urban greenery raises water demand in a semi-arid catchment. Public health researchers have repeatedly linked urban heat exposure to heat stroke, cardiovascular stress, and excess mortality among elderly and outdoor-working populations, and the developing cities of South Asia are among the most vulnerable because adaptive infrastructure, from shaded streets to reliable cooling, remains unevenly distributed.</p>
<p>What makes this study especially valuable is its setting. Most urban heat island research concentrates on large lowland megacities, where the signal is easiest to isolate. Mountain and plateau cities present a more complicated picture because topography, elevation, and aspect already create strong temperature gradients before urbanization adds its own. By demonstrating that settlement growth in such terrain produces measurable, decadal-scale shifts in both the thermal and hydrological regimes, the authors highlight a class of rapidly growing cities, from the Himalayan foothills to the Iranian plateau and the Andean valleys, whose climate dynamics are poorly captured by models and monitoring networks designed for flat terrain. The findings suggest that these effects remain largely unrecognized in developing regions, contributing to a gradual atmospheric degradation that policy has yet to confront.</p>
<p>The authors argue that neither prevention nor cure can wait for perfect data. They call for coordinated action on demographic planning and institutional capacity-building, and they advocate incorporating geo-artificial-intelligence approaches, in which machine learning applied to satellite archives can forecast land cover change and its climatic consequences before development decisions are finalized. Such tools could allow planners in Islamabad and cities like it to test scenarios, locating green corridors where they will deliver the greatest cooling, protecting recharge zones from sealing, and steering growth away from the most thermally sensitive slopes. The study speaks directly to urban planners, policymakers, and climate specialists aiming to build climate-compatible cities, and its message is blunt: in semi-arid mountain ecosystems, the link between urban expansion and atmospheric stress is now measurable, and the window for affordable adaptation is narrowing with every hectare of land that disappears under concrete.</p>
<p><strong>Subject of Research:</strong> Impacts of land cover change on the urban heat island effect and evapotranspiration in the mountain and plateau region of Islamabad and Rawalpindi, Pakistan</p>
<p><strong>Article Title:</strong> Assessing the impacts of land cover changes on urban heat island effect and evapotranspiration patterns in mountain and plateau regions</p>
<p><strong>Article References:</strong> Islam, A., Ali, S. M., Kanwal, A., Zaman-ul-Haq, M., Tariq, A., Ali, I., Adnan, S., Faqeih, K. Y., Alamri, S. M., Alamery, E. R., &amp; Bokhari, S. A. (2026). Assessing the impacts of land cover changes on urban heat island effect and evapotranspiration patterns in mountain and plateau regions. <em>Theoretical and Applied Climatology, 157</em>(9), Article 607. <a href="https://doi.org/10.1007/s00704-026-06544-w" rel="noopener noreferrer">https://doi.org/10.1007/s00704-026-06544-w</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1007/s00704-026-06544-w" rel="noopener noreferrer">10.1007/s00704-026-06544-w</a></p>
<p><strong>Keywords:</strong> urban heat island, land surface temperature, evapotranspiration, SEBAL, Landsat, land cover change, Islamabad, Rawalpindi, remote sensing, urbanization, NDVI, surface albedo</p>
]]></content:encoded>
					
		
		
		<post-id xmlns="com-wordpress:feed-additions:1">252465</post-id>	</item>
		<item>
		<title>New Global Albedo Dataset Could Reshape How We Count the Climate Cost of Land Use</title>
		<link>https://scienmag.com/new-global-albedo-dataset-could-reshape-how-we-count-the-climate-cost-of-land-use/</link>
		
		<dc:creator><![CDATA[Sloane Callahan]]></dc:creator>
		<pubDate>Sun, 04 Oct 2026 21:57:21 +0000</pubDate>
				<category><![CDATA[Climate]]></category>
		<category><![CDATA[albedo's influence on carbon footprint]]></category>
		<category><![CDATA[albedo's role in greenhouse gas emission calculations]]></category>
		<category><![CDATA[biogeophysical effects]]></category>
		<category><![CDATA[carbon accounting]]></category>
		<category><![CDATA[climate impact assessment]]></category>
		<category><![CDATA[Climate Policy]]></category>
		<category><![CDATA[climate policy and land use impact analysis]]></category>
		<category><![CDATA[environmental impact assessment]]></category>
		<category><![CDATA[Global albedo dataset for climate impact assessment]]></category>
		<category><![CDATA[implications of land surface albedo on climate mitigation strategies]]></category>
		<category><![CDATA[integrating land surface reflectance into environmental accounting]]></category>
		<category><![CDATA[land surface reflectivity and climate change]]></category>
		<category><![CDATA[land use]]></category>
		<category><![CDATA[land-cover change]]></category>
		<category><![CDATA[Life Cycle Assessment]]></category>
		<category><![CDATA[MODIS]]></category>
		<category><![CDATA[new methodology for land surface reflectivity measurement]]></category>
		<category><![CDATA[radiative forcing]]></category>
		<category><![CDATA[remote sensing]]></category>
		<category><![CDATA[remote sensing and satellite data for albedo mapping]]></category>
		<category><![CDATA[spatially resolved land cover albedo data]]></category>
		<category><![CDATA[surface albedo]]></category>
		<category><![CDATA[surface albedo and energy balance in climate models]]></category>
		<guid isPermaLink="false">https://scienmag.com/?p=235842</guid>

					<description><![CDATA[Researchers have built a global dataset of realistic surface albedo values for 22 land cover types, revealing that simplified methods underestimate albedo and paving the way for climate impact assessments that account for how land reflects sunlight.]]></description>
										<content:encoded><![CDATA[<p>When a forest is cleared, a field is plowed, or a city spreads across farmland, the climate consequences are usually tallied in tonnes of carbon dioxide. But there is a second, quieter lever on the planet&#8217;s energy balance that most environmental accounting simply ignores: how brightly the land surface reflects sunlight. A new study published in the Journal of Industrial Ecology by Kathryn Loog of Polytechnique Montreal, together with Anders Bjørn of the Technical University of Denmark and Manuele Margni of Polytechnique Montreal and HES-SO Valais Wallis, tackles this blind spot head-on. The researchers have built a global, spatially and temporally resolved dataset of surface albedo values for 22 land cover types, along with a methodology designed to make those values usable in the environmental impact assessments that guide corporate carbon accounting, life cycle assessment, and climate policy. The work, published on 18 July 2026, represents one of the most concerted efforts yet to bring the reflective power of the land surface into the same ledger as greenhouse gas emissions.</p>
<p>Surface albedo, the fraction of incoming solar radiation that a surface reflects back toward the sky, is a recognized driver of climate change in the physical science literature. Snow-covered boreal forests, dark conifer canopies, bright croplands, and grey urban rooftops each interact with sunlight in profoundly different ways. When land cover changes, so does the amount of solar energy absorbed at the surface, producing a radiative forcing that can either warm or cool the planet independently of any carbon flux. The Intergovernmental Panel on Climate Change acknowledges these biogeophysical effects, and studies stretching back to Robert Betts&#8217; landmark 2000 paper in Nature have shown that afforestation in snowy high latitudes can offset, or even reverse, the carbon benefits of new trees because forests are darker than snow. Yet despite this well-established physics, albedo impacts are rarely quantified alongside greenhouse gas emissions in the assessment frameworks that actually inform decisions.</p>
<p>The barrier, the authors argue, has been data. To calculate the albedo change caused by converting one land cover type to another, an analyst needs albedo values for both the original and the new land cover at the same location, under the same atmospheric conditions, and at the same time of year. Existing simplified methods typically rely on single, static albedo values per land cover type, values that do not capture how albedo fluctuates through the day as the sun&#8217;s angle changes, nor how it varies with real atmospheric conditions such as cloud cover and aerosol loading. Albedo is not a fixed property of a surface: it depends on solar zenith angle, on whether the sky is clear or cloudy, on snow cover, and on the structure of vegetation canopies. Averaging all of that complexity into one number per land cover type introduces systematic error, and until now there has been no dataset designed specifically to support the direct calculation of albedo change between land cover types.</p>
<p>Loog and her colleagues set out to close that gap with a methodology that estimates daily-mean blue-sky albedo values for multiple land cover types at the same location. The term blue-sky is significant: it refers to albedo under realistic, mixed atmospheric conditions rather than the idealized clear-sky or entirely overcast scenarios that many remote sensing products assume. The approach draws on MODIS satellite data, accessed through Google Earth Engine, including the MODIS BRDF and albedo model parameters and land cover products, combined with ERA5 reanalysis data from the Copernicus Climate Data Store to characterize atmospheric conditions. By anchoring the estimates to real, spatially specific observations and weighting them toward realistic skies, the methodology produces albedo values that reflect what the atmosphere actually encounters, not a laboratory idealization.</p>
<p>The result is a global climatological dataset of surface albedo values for 22 distinct land cover types, each resolved in space and time. A crucial validation step was statistical: the researchers tested whether the albedo values assigned to each land cover type were genuinely distinguishable from one another, and found that all 22 types were statistically distinct. That matters because the entire premise of land-cover-based albedo accounting rests on the assumption that different land covers have meaningfully different reflectivities. If the distributions overlapped heavily, converting between two types would produce noise rather than signal. The statistical separation confirms that the dataset carries real, physically meaningful information about how land cover shapes the surface energy balance.</p>
<p>The comparison with existing simplified methods is where the study delivers its most striking numbers. When the new dataset was set against values derived from conventional approaches that ignore diurnal fluctuations and realistic atmospheric conditions, the simplified values underestimated surface albedo by 2.7 to 5.8 percent on average. That may sound modest, but the distribution of errors is wide: in some cases the discrepancies reached more than plus or minus 50 percent. For an analyst calculating the climate impact of converting cropland to forest, or of an urban expansion project, an error of that magnitude in the underlying albedo values could flip the sign of the estimated radiative forcing, turning a projected warming into a projected cooling or vice versa. In other words, the simplified numbers are not just imprecise; in edge cases they can be qualitatively wrong.</p>
<p>Why does the diurnal cycle matter so much? Albedo generally increases as the sun sits low in the sky, because light strikes surfaces at grazing angles and interacts with canopy structure and roughness in ways that enhance reflection. A daily-mean albedo that properly weights this variation, hour by hour, differs systematically from a snapshot taken when the satellite happens to pass overhead, typically in mid-morning when the sun is high and albedo is near its daily minimum. Atmospheric conditions compound the effect, since clouds and aerosols alter both the intensity and the angular distribution of incoming radiation. By integrating these effects, the new methodology produces values that better represent the true daily exchange of energy between the surface and the atmosphere, which is precisely the quantity that radiative forcing calculations need.</p>
<p>The practical implications reach into several influential arenas. In life cycle assessment, the standard tool for evaluating the environmental footprint of products and services, land use impacts have long been dominated by biogeochemical considerations such as carbon stock changes, while biogeophysical effects like albedo have remained optional or absent. Researchers including R. M. Bright and collaborators have proposed metrics for converting albedo-induced radiative forcing into carbon dioxide equivalence, and case studies on biofuels, forestry, pavements, and greenhouse agriculture have demonstrated that albedo can rival carbon in importance for certain land-intensive systems. A reliable, globally consistent albedo dataset removes one of the main technical excuses for leaving these effects out. The same logic applies to national and corporate carbon accounting under frameworks such as the Greenhouse Gas Protocol, whose land sector guidance has been grappling with how to treat biogeophysical impacts, and to the evaluation of nature-based climate solutions, where recent studies have warned that tree planting at northern high latitudes may be far less climate-positive than carbon accounting alone suggests.</p>
<p>The dataset and the tooling around it are openly available. The albedo dataset itself is deposited in a Zenodo repository, all input datasets are public, and the authors have released their scripts on GitHub, including a Python-based tool that lets users retrieve albedo values at a 500-meter spatial scale, matching the resolution of the MODIS land cover products. Mann-Kendall trend test results and proxy comparison outputs are available in a separate repository. This openness lowers the barrier for practitioners in life cycle assessment, carbon accounting, and policy analysis to begin experimenting with albedo-inclusive assessments, and it invites scrutiny and improvement of the methodology by the wider research community.</p>
<p>There remain challenges on the road from dataset to decision. Translating albedo change into a CO2-equivalent metric involves methodological choices about time horizons and the decay of radiative forcing that are still actively debated in the literature. The dataset is climatological, describing typical conditions rather than year-to-year variability, and land cover classifications at 500-meter resolution inevitably simplify the mosaic of real landscapes. Nonetheless, the study provides what has arguably been the missing ingredient: a defensible, spatially and temporally specific, physically realistic set of albedo values that can be dropped directly into impact assessment calculations. As governments and corporations increasingly lean on land-based climate strategies, from reforestation to regenerative agriculture to urban greening, the energy reflected back to space by those landscapes will no longer be an afterthought. With this dataset, the mirror-like half of the land-climate equation finally has numbers that accountants, assessors, and policymakers can work with.</p>
<p><strong>Subject of Research:</strong> Surface albedo effects of land cover change for climate impact assessment</p>
<p><strong>Article Title:</strong> Enhancing climate impact assessment with surface albedo effects of land cover changes: methodology and dataset</p>
<p><strong>Article References:</strong> Loog, K., Bjørn, A., &amp; Margni, M. (2026). Enhancing climate impact assessment with surface albedo effects of land cover changes: methodology and dataset. <em>Journal of Industrial Ecology, 30</em>(4), 1869-1884. <a href="https://doi.org/10.1007/s44498-026-00127-8" rel="noopener noreferrer">https://doi.org/10.1007/s44498-026-00127-8</a></p>
<p><strong>Image Credits:</strong> AI Generated</p>
<p><strong>DOI:</strong> <a href="https://doi.org/10.1007/s44498-026-00127-8" rel="noopener noreferrer">10.1007/s44498-026-00127-8</a></p>
<p><strong>Keywords:</strong> surface albedo, land cover change, climate impact assessment, life cycle assessment, radiative forcing, MODIS, remote sensing, carbon accounting, land use, climate policy, biogeophysical effects, environmental impact assessment</p>
]]></content:encoded>
					
		
		
		<post-id xmlns="com-wordpress:feed-additions:1">235842</post-id>	</item>
	</channel>
</rss>
